, president obama's praised the people of boston. >> they failed because as americans, we refuse to be terrorized. >> reporter: the president vowed to get all the remaining questions about the bombings answered and he cautioned americans against a rush to judgment about the brother's motive or their background. >> a u.s. government official says at this point there is no known tie between the suspects and any extremist groups. but have learned quite a bit about the brothers. our coverage continues with jana katsuyama. she's been digging into their past and she joins with us now live with new information tonight about their background. >> we certainly are learning more. many people who knew the brothers describe the boys as smart and athletic. not someone they would associate with the boston massachusetts bombings. his older brother practiced martial arts. today the suspect's parents spoke in shock from the russian republic. the father calling the younger son a true angel and said he spoke with his eldest son this week. >> he said everything is okay. i asked him, how is dzhokhar.